Systematic analyses of the formation water and natural gas geochemistry in the Central Uplift of the Tarim Basin （CUTB） show that gas invasion at the late stage is accompanied by an increase of the contents of HeS a...Systematic analyses of the formation water and natural gas geochemistry in the Central Uplift of the Tarim Basin （CUTB） show that gas invasion at the late stage is accompanied by an increase of the contents of HeS and CO2 in natural gas, by the forming of the high total dissolved solids formation water, by an increase of the content of HCO3^-, relative to Cl^-, by an increase of the 2nd family ions （Ca^2＋, Mg^2＋, Sr^2＋ and Ba^2＋） and by a decrease of the content of SO4^2-, relative to Cl^-. The above phenomena can be explained only by way of thermochemicai sulfate reduction （TSR）. TSR often occurs in the transition zone of oil and water and is often described in the following reaction formula： ∑CH＋CaSO4＋H-2O→H2S＋CO2＋CaCO3. （1） Dissolved SO4^2- in the formation water is consumed in the above reaction, when HeS and CO2 are generated, resulting in a decrease of SO4^2- in the formation water and an increase of both HeS and CO2 in the natural gas. If formation water exists, the generated CO2 will go on reacting with the carbonate to form bicarbonate, which can be dissolved in the formation water, thus resulting in the enrichment of Ca^2＋ and HCO3^-. The above reaction can be described by the following equation： CO2＋HeO＋CaCO3→Ca^2＋＋2HCO3^-. The stratigraphic temperatures of the Cambrian and lower Ordovician in CUTB exceeded 120℃, which is the minimum for TSR to occur. At the same time, dolomitization, which might be a direct result of TSR, has been found in both the Cambrian and the lower Ordovician. The above evidence indicates that TSR is in an active reaction, providing a novel way to reevaluate the exploration potentials of natural gas in this district.展开更多
Subtropical sediment cores （QA09-1 and QA12-9） from the coastal zone of Qi’ao Island in the Zhujiang River Estuary were used to determine the rates of sulfate reduction and their response to experimental tempera-tu...Subtropical sediment cores （QA09-1 and QA12-9） from the coastal zone of Qi’ao Island in the Zhujiang River Estuary were used to determine the rates of sulfate reduction and their response to experimental tempera-ture changes. The depth distribution of the sulfate reduction rates was measured from whole-core incu-bations with radioactive tracer35SO42-, and peaks of 181.19 nmol/（cm3·d） and 107.49 nmol/（cm3·d） were exhibited at stations QA09-1 and QA12-9, respectively. The profiles of the pore water methane and sulfate concentrations demonstrated that anaerobic oxidation of methane occurred in the study area, which result-ed in an increase in the sulfate reduction rate at the base of the sulfate-reducing zone. Meanwhile, the sulfate concentration was not a major limiting factor for controlling the rates of sulfate reduction. In addition, the incubation of the sediment slurries in a block with a temperature gradient showed that the optimum tem-perature for the sulfate reduction reaction was 36°C. The Arrhenius plot was linear from the lowest tempera-ture to the optimum temperature, and the activation energy was at the lower end of the range of previously reported values. The results suggested that the ambient temperature regime of marine environments prob-ably selected for the microbial population with the best-suited physiology for the respective environment.展开更多
To evaluate the feasibility of recovering Pb and Zn sulfides and Ag-containing minerals from Zn leaching residue by the process of reduction roasting followed by flotation,the reaction behaviors of Pb and Zn sulfates ...To evaluate the feasibility of recovering Pb and Zn sulfides and Ag-containing minerals from Zn leaching residue by the process of reduction roasting followed by flotation,the reaction behaviors of Pb and Zn sulfates during this process were investigated.Chemical analysis showed that the transformation ratios of PbSO4 and ZnSO4 could reach 65.51%and 52.12%,respectively,after reduction roasting,and the introduction of a sulfidation agent could improve the transformation ratios of these sulfates.scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS)revealed that temperature obviously affects the particle size,crystal growth,and morphology of the artificial Pb and Zn sulfide minerals.Particle size analysis demonstrated that the particle size of the materials increases after roasting.Flotation tests revealed that a flotation concentrate composed of 12.01wt%Pb,27.78wt%Zn,and 6.975×10^(−2)wt%Ag with recoveries of 60.54%,29.24%,and 57.64%,respectively,could be obtained after roasting.展开更多
In order to decrease the solubility of PbSO4 and enhance lead recovery from PbSO4 bearing wastes, CO was employed as a reductant to transform PbSO4 into Pb S. Reaction system was established and reductive thermodynami...In order to decrease the solubility of PbSO4 and enhance lead recovery from PbSO4 bearing wastes, CO was employed as a reductant to transform PbSO4 into Pb S. Reaction system was established and reductive thermodynamics of PbSO4 was calculated by software HSC 5.0. The effects of gas concentration, reaction temperature, time and mass of sample on reduction of PbSO4 were examined by thermogravimetry(TG) and XRD. Roasting tests further verify the conclusions of thermodynamic and TG analyses. The results show that increasing temperature in the reasonable range and CO content are favorable for the formation of Pb S. The reduction process is controlled by chemical reaction and calculation value of the activation energy is 47.88 k J/mol.展开更多
Thermochemical sulfate reduction （TSR） is the reaction between anhydrite and petroleum fluids at elevated temperatures to produce H2S and CO2. TSR has been studied in many sedimentary basins such as China＇s Sichuan...Thermochemical sulfate reduction （TSR） is the reaction between anhydrite and petroleum fluids at elevated temperatures to produce H2S and CO2. TSR has been studied in many sedimentary basins such as China＇s Sichuan and Tarim basins because it has a profound impact on the commercial viability of petroleum resources, with HzS typically being undesirable.展开更多
In this paper, the relationship between sulfate reduction potential and mercury methylation potential was studied in the Aha, Baihua and Hongfeng reservoirs from Guiyang City. The methylmercury (MeHg) concentrations o...In this paper, the relationship between sulfate reduction potential and mercury methylation potential was studied in the Aha, Baihua and Hongfeng reservoirs from Guiyang City. The methylmercury (MeHg) concentrations of lake water in the Aha Reservoir were greatly elevated as compared to those of the Hongfeng and Baihua reservoirs, which was correlated with its distinctly high SRB abundance, SO42-, and S2- concentrations. Among the three reservoirs, however, the highest MeHg was observed in in the top several centimenters of pore water profile in the Hongfeng Reservoir where the lowest S2- in pore water occurred. The distributions of MeHg in lake water and pore water showed the highest methylation potential occurred at water-sediment surface for the Aha Reservoir and the in the top several centimenters of sediments for the Hongfeng Reservoir. It is guessed that the highest mercury methylation only occurs at the sites with certain sulfide concentrations.展开更多
In order to investigate the change of ecological characteristics due to the decrease of COD/SO42- ratio during sulfate reduction, continuous-flew tests were conducted in an acidogenic sulfate-reducing reactor with mol...In order to investigate the change of ecological characteristics due to the decrease of COD/SO42- ratio during sulfate reduction, continuous-flew tests were conducted in an acidogenic sulfate-reducing reactor with molasses wastewater as sole organic carbon source and sodium sulfate as electron acceptor, and the change of pH value, oxidation reduction potential (ORP), volatile fat acids (VFAs), alkalinity (ALK) and the predominant populations with COD/SO42- ratio decreasing from 4. 2 to 2. 0 were investigated. The experimental results demonstrated that, with decreasing COD/SO42- ratio, ORP and ALK increased, pH value decreased, and the proportion of acetic acid in terminal products decreased significantly, and a stable - type microbial community with high COD/SO42- ratio was converted into a sub -stable -type one with low COD/SO42- ratio.展开更多
Acid-producing phase reactor of two-phase anaerobic treatment process has remarkable advantages treating sulfate-laden wastewater. In order to investigate SRB population's capability of utilizing substrate and the...Acid-producing phase reactor of two-phase anaerobic treatment process has remarkable advantages treating sulfate-laden wastewater. In order to investigate SRB population's capability of utilizing substrate and the microbial acidification type formed during the course of sulfate reduction, continuous-flow and batch tests were conducted in a continuous stirred tank bio-film reactor supplied with sodium sulfate as electron acceptor. The experimental results demonstrated that the acidification type formed b...展开更多
The kinetic characteristics of alkenes involved in thermochemical sulfate reduction (TSR) have been never reported in geological literature. In this study, TSR by ethene under hydrothermal conditions was performed in ...The kinetic characteristics of alkenes involved in thermochemical sulfate reduction (TSR) have been never reported in geological literature. In this study, TSR by ethene under hydrothermal conditions was performed in the constrained simulation experiments. Typical TSR products consisted of H<sub>2</sub>S, CO<sub>2</sub>, mercaptans, sulfides, thiophenes derivatives and benzothiophene. The apparent activation energy <i>E</i> and apparent frequency factor <i>A</i> for TSR by ethene were determined as 76.370 kJ/mol and 4.579 s<sup>-1</sup>, respectively. The lower activation energy for ethene involved in TSR relative to ethane suggested that the reactivity of ethene is much higher than that of ethane, in accordance with the thermodynamic analysis. Rate constants were determined experimentally using first-order kinetics extrapolate to MgSO<sub>4</sub> half-lives of 67.329 years - 3.053 years in deep burial diagenetic settings (120°C - 180°C). These values demonstrate that the reaction rate for TSR by ethene is extraordinarily fast in high-temperature gas reservoirs (120°C - 180°C). Consequently, the newly formed ethene from thermal cracking and TSR alteration of natural gas and/or petroleum could not survive after TSR process and were rarely detected in natural TSR reservoirs.展开更多
基金supported by the State 973 Project(Grant No.2006CB202308)the National Natural Science Foundation of China(Grant No.40872097)
文摘Systematic analyses of the formation water and natural gas geochemistry in the Central Uplift of the Tarim Basin （CUTB） show that gas invasion at the late stage is accompanied by an increase of the contents of HeS and CO2 in natural gas, by the forming of the high total dissolved solids formation water, by an increase of the content of HCO3^-, relative to Cl^-, by an increase of the 2nd family ions （Ca^2＋, Mg^2＋, Sr^2＋ and Ba^2＋） and by a decrease of the content of SO4^2-, relative to Cl^-. The above phenomena can be explained only by way of thermochemicai sulfate reduction （TSR）. TSR often occurs in the transition zone of oil and water and is often described in the following reaction formula： ∑CH＋CaSO4＋H-2O→H2S＋CO2＋CaCO3. （1） Dissolved SO4^2- in the formation water is consumed in the above reaction, when HeS and CO2 are generated, resulting in a decrease of SO4^2- in the formation water and an increase of both HeS and CO2 in the natural gas. If formation water exists, the generated CO2 will go on reacting with the carbonate to form bicarbonate, which can be dissolved in the formation water, thus resulting in the enrichment of Ca^2＋ and HCO3^-. The above reaction can be described by the following equation： CO2＋HeO＋CaCO3→Ca^2＋＋2HCO3^-. The stratigraphic temperatures of the Cambrian and lower Ordovician in CUTB exceeded 120℃, which is the minimum for TSR to occur. At the same time, dolomitization, which might be a direct result of TSR, has been found in both the Cambrian and the lower Ordovician. The above evidence indicates that TSR is in an active reaction, providing a novel way to reevaluate the exploration potentials of natural gas in this district.
基金The National Natural Science Foundation of China under contract Nos 40803020 and 41176065
文摘Subtropical sediment cores （QA09-1 and QA12-9） from the coastal zone of Qi’ao Island in the Zhujiang River Estuary were used to determine the rates of sulfate reduction and their response to experimental tempera-ture changes. The depth distribution of the sulfate reduction rates was measured from whole-core incu-bations with radioactive tracer35SO42-, and peaks of 181.19 nmol/（cm3·d） and 107.49 nmol/（cm3·d） were exhibited at stations QA09-1 and QA12-9, respectively. The profiles of the pore water methane and sulfate concentrations demonstrated that anaerobic oxidation of methane occurred in the study area, which result-ed in an increase in the sulfate reduction rate at the base of the sulfate-reducing zone. Meanwhile, the sulfate concentration was not a major limiting factor for controlling the rates of sulfate reduction. In addition, the incubation of the sediment slurries in a block with a temperature gradient showed that the optimum tem-perature for the sulfate reduction reaction was 36°C. The Arrhenius plot was linear from the lowest tempera-ture to the optimum temperature, and the activation energy was at the lower end of the range of previously reported values. The results suggested that the ambient temperature regime of marine environments prob-ably selected for the microbial population with the best-suited physiology for the respective environment.
基金the National Natural Science Foundation of China(No.51964027)the Yunnan Province Applied Basic Research Project,China(No.2017FB084)+1 种基金the Foundation of Yunnan’s Education Ministry,China(No.2019J0037)the Testing and Analyzing Funds of Kunming University of Science and Technology(No.2018T20150055).
文摘To evaluate the feasibility of recovering Pb and Zn sulfides and Ag-containing minerals from Zn leaching residue by the process of reduction roasting followed by flotation,the reaction behaviors of Pb and Zn sulfates during this process were investigated.Chemical analysis showed that the transformation ratios of PbSO4 and ZnSO4 could reach 65.51%and 52.12%,respectively,after reduction roasting,and the introduction of a sulfidation agent could improve the transformation ratios of these sulfates.scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS)revealed that temperature obviously affects the particle size,crystal growth,and morphology of the artificial Pb and Zn sulfide minerals.Particle size analysis demonstrated that the particle size of the materials increases after roasting.Flotation tests revealed that a flotation concentrate composed of 12.01wt%Pb,27.78wt%Zn,and 6.975×10^(−2)wt%Ag with recoveries of 60.54%,29.24%,and 57.64%,respectively,could be obtained after roasting.
基金Project(51204210)supported by the National Natural Science Foundation of ChinaProject(2011AA061001)supported by the National High Technology Research and Development Program of ChinaProject(2012BAC12B04)supported by the National Science and Technology Pillar Program during the Twelfth Five-Year Plan of China
文摘In order to decrease the solubility of PbSO4 and enhance lead recovery from PbSO4 bearing wastes, CO was employed as a reductant to transform PbSO4 into Pb S. Reaction system was established and reductive thermodynamics of PbSO4 was calculated by software HSC 5.0. The effects of gas concentration, reaction temperature, time and mass of sample on reduction of PbSO4 were examined by thermogravimetry(TG) and XRD. Roasting tests further verify the conclusions of thermodynamic and TG analyses. The results show that increasing temperature in the reasonable range and CO content are favorable for the formation of Pb S. The reduction process is controlled by chemical reaction and calculation value of the activation energy is 47.88 k J/mol.
基金supported by the National Natural Science Foundation of China(grant No.41530314)Geological Survey Program(grant No.1212291313016001)
文摘Thermochemical sulfate reduction （TSR） is the reaction between anhydrite and petroleum fluids at elevated temperatures to produce H2S and CO2. TSR has been studied in many sedimentary basins such as China＇s Sichuan and Tarim basins because it has a profound impact on the commercial viability of petroleum resources, with HzS typically being undesirable.
基金financially supported by Natural Science Foundation of China(Nos.41063006 and 40973083)"211 Project"Key Discipline Construction(KST2009003)the Guizhou Key Laboratory Construction Program(Qiankeheji-Z-[2012]4012)
文摘In this paper, the relationship between sulfate reduction potential and mercury methylation potential was studied in the Aha, Baihua and Hongfeng reservoirs from Guiyang City. The methylmercury (MeHg) concentrations of lake water in the Aha Reservoir were greatly elevated as compared to those of the Hongfeng and Baihua reservoirs, which was correlated with its distinctly high SRB abundance, SO42-, and S2- concentrations. Among the three reservoirs, however, the highest MeHg was observed in in the top several centimenters of pore water profile in the Hongfeng Reservoir where the lowest S2- in pore water occurred. The distributions of MeHg in lake water and pore water showed the highest methylation potential occurred at water-sediment surface for the Aha Reservoir and the in the top several centimenters of sediments for the Hongfeng Reservoir. It is guessed that the highest mercury methylation only occurs at the sites with certain sulfide concentrations.
基金Sponsored by the National Natural Science Foundation of China(Grant No. 50208006)the Scientific Research Foundation of Harbin Institute of Technology(Grant No. HIT. 2001.51)
文摘In order to investigate the change of ecological characteristics due to the decrease of COD/SO42- ratio during sulfate reduction, continuous-flew tests were conducted in an acidogenic sulfate-reducing reactor with molasses wastewater as sole organic carbon source and sodium sulfate as electron acceptor, and the change of pH value, oxidation reduction potential (ORP), volatile fat acids (VFAs), alkalinity (ALK) and the predominant populations with COD/SO42- ratio decreasing from 4. 2 to 2. 0 were investigated. The experimental results demonstrated that, with decreasing COD/SO42- ratio, ORP and ALK increased, pH value decreased, and the proportion of acetic acid in terminal products decreased significantly, and a stable - type microbial community with high COD/SO42- ratio was converted into a sub -stable -type one with low COD/SO42- ratio.
基金Supported by the National Natural Science Foundation of China (No.50208006).
文摘Acid-producing phase reactor of two-phase anaerobic treatment process has remarkable advantages treating sulfate-laden wastewater. In order to investigate SRB population's capability of utilizing substrate and the microbial acidification type formed during the course of sulfate reduction, continuous-flow and batch tests were conducted in a continuous stirred tank bio-film reactor supplied with sodium sulfate as electron acceptor. The experimental results demonstrated that the acidification type formed b...
文摘The kinetic characteristics of alkenes involved in thermochemical sulfate reduction (TSR) have been never reported in geological literature. In this study, TSR by ethene under hydrothermal conditions was performed in the constrained simulation experiments. Typical TSR products consisted of H<sub>2</sub>S, CO<sub>2</sub>, mercaptans, sulfides, thiophenes derivatives and benzothiophene. The apparent activation energy <i>E</i> and apparent frequency factor <i>A</i> for TSR by ethene were determined as 76.370 kJ/mol and 4.579 s<sup>-1</sup>, respectively. The lower activation energy for ethene involved in TSR relative to ethane suggested that the reactivity of ethene is much higher than that of ethane, in accordance with the thermodynamic analysis. Rate constants were determined experimentally using first-order kinetics extrapolate to MgSO<sub>4</sub> half-lives of 67.329 years - 3.053 years in deep burial diagenetic settings (120°C - 180°C). These values demonstrate that the reaction rate for TSR by ethene is extraordinarily fast in high-temperature gas reservoirs (120°C - 180°C). Consequently, the newly formed ethene from thermal cracking and TSR alteration of natural gas and/or petroleum could not survive after TSR process and were rarely detected in natural TSR reservoirs.
